Revert "Revert "Metadata handling rewrite""

This reverts commit 5e01e2ac977655aa074faf7fde0a74298f5e4c55.
diff --git a/test/core/end2end/tests/disappearing_server.c b/test/core/end2end/tests/disappearing_server.c
index 8ebf7e6..a013721 100644
--- a/test/core/end2end/tests/disappearing_server.c
+++ b/test/core/end2end/tests/disappearing_server.c
@@ -93,13 +93,13 @@
   grpc_call_details call_details;
   grpc_status_code status;
   grpc_call_error error;
-  char *details = NULL;
-  size_t details_capacity = 0;
+  grpc_slice details;
   int was_cancelled = 2;
 
   c = grpc_channel_create_call(
-      f->client, NULL, GRPC_PROPAGATE_DEFAULTS, f->cq, "/foo",
-      get_host_override_string("foo.test.google.fr:1234", config), deadline,
+      f->client, NULL, GRPC_PROPAGATE_DEFAULTS, f->cq,
+      grpc_slice_from_static_string("/foo"),
+      get_host_override_slice("foo.test.google.fr:1234", config), deadline,
       NULL);
   GPR_ASSERT(c);
 
@@ -128,7 +128,6 @@
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
-  op->data.recv_status_on_client.status_details_capacity = &details_capacity;
   op->flags = 0;
   op->reserved = NULL;
   op++;
@@ -156,7 +155,8 @@
   op->op = GRPC_OP_SEND_STATUS_FROM_SERVER;
   op->data.send_status_from_server.trailing_metadata_count = 0;
   op->data.send_status_from_server.status = GRPC_STATUS_UNIMPLEMENTED;
-  op->data.send_status_from_server.status_details = "xyz";
+  grpc_slice status_details = grpc_slice_from_static_string("xyz");
+  op->data.send_status_from_server.status_details = &status_details;
   op->flags = 0;
   op->reserved = NULL;
   op++;
@@ -174,13 +174,13 @@
   cq_verify(cqv);
 
   GPR_ASSERT(status == GRPC_STATUS_UNIMPLEMENTED);
-  GPR_ASSERT(0 == strcmp(details, "xyz"));
-  GPR_ASSERT(0 == strcmp(call_details.method, "/foo"));
+  GPR_ASSERT(0 == grpc_slice_str_cmp(details, "xyz"));
+  GPR_ASSERT(0 == grpc_slice_str_cmp(call_details.method, "/foo"));
   validate_host_override_string("foo.test.google.fr:1234", call_details.host,
                                 config);
   GPR_ASSERT(was_cancelled == 1);
 
-  gpr_free(details);
+  grpc_slice_unref(details);
   grpc_metadata_array_destroy(&initial_metadata_recv);
   grpc_metadata_array_destroy(&trailing_metadata_recv);
   grpc_metadata_array_destroy(&request_metadata_recv);